Existing general X-ray devices employ a tube voltage ranged from 50 kV to 125 kV. Energy in such a range is too high for a child at age of 0-3. Since a child's body is small and his/her bones are not calcified completely, substantially all X-ray transmits through the body, thus it is difficult to obtain a clear X-ray photograph. A special purpose X-ray device for the mammography diagnose employs a typical tube voltage ranged from 20 kV to 32 kV, which is not applicable for the child at the age of 0-3 years.
In addition, a moving body would produce a moving artificial image on the film during photographing, which causes the image unclear. It is difficult for the child at the age of 0-3 to keep still status as an adult during an X-ray irradiation measurement. Therefore, a general X-ray device can not obtain the clear X-ray photograph of a child due to the child's frequent movement. Similarly, breath and heart beat would also affect the definition of the X-ray irradiation image.
Furthermore, since the child is in the stage of rapid growth, there are a lot juvenile cells in the body, which are more sensitive to ionizing irradiation, the X-ray are harmful to the child especially. Therefore, it is necessary for the child to avoid a large area of X-ray irradiation so as to reduce received dose of unnecessary X-ray irradiation. Thus, it should only irradiate necessary parts and shield other parts from being irradiated. Moreover, X-ray technicians, doctors and parents of a sick child should avoid the X-ray radiation. However, such an X-ray irradiation protection is not considered for a general X-ray device.